I have a table flat surface made from aluminum, and the table legs are made from medium carbon steel. What are 3 welding processes that could be used to weld the legs to the flat surface.
Can't be done . Soldering and brazing physical properties would be poor. I think there is one possibility , which you can not afford, explosion bonding . A piece of aluminum is forced against steel by explosive force. Even that would be a challenge because of the very large differences in properties. Then aluminum would be welded to the aluminum side and steel welded to the steel side ; still I see a lot of problems. Think epoxy or bolts.